/*
 * Copyright 1997 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */

package org.loon.framework.android.game.core.graphics.geom;

import java.util.*;

/**
 * A utility class to iterate over the path segments of an rounded rectangle
 * through the PathIterator interface.
 * 
 * @author Jim Graham
 */
class RoundRectIterator implements PathIterator {
	double x, y, w, h, aw, ah;
	AffineTransform affine;
	int index;

	RoundRectIterator(RoundRectangle2D rr, AffineTransform at) {
		this.x = rr.getX();
		this.y = rr.getY();
		this.w = rr.getWidth();
		this.h = rr.getHeight();
		this.aw = Math.min(w, Math.abs(rr.getArcWidth()));
		this.ah = Math.min(h, Math.abs(rr.getArcHeight()));
		this.affine = at;
		if (aw < 0 || ah < 0) {
			// Don't draw anything...
			index = ctrlpts.length;
		}
	}

	/**
	 * Return the winding rule for determining the insideness of the path.
	 * 
	 * @see #WIND_EVEN_ODD
	 * @see #WIND_NON_ZERO
	 */
	public int getWindingRule() {
		return WIND_NON_ZERO;
	}

	/**
	 * Tests if there are more points to read.
	 * 
	 * @return true if there are more points to read
	 */
	public boolean isDone() {
		return index >= ctrlpts.length;
	}

	/**
	 * Moves the iterator to the next segment of the path forwards along the
	 * primary direction of traversal as long as there are more points in that
	 * direction.
	 */
	public void next() {
		index++;
	}

	private static final double angle = Math.PI / 4.0;
	private static final double a = 1.0 - Math.cos(angle);
	private static final double b = Math.tan(angle);
	private static final double c = Math.sqrt(1.0 + b * b) - 1 + a;
	private static final double cv = 4.0 / 3.0 * a * b / c;
	private static final double acv = (1.0 - cv) / 2.0;

	// For each array:
	// 4 values for each point {v0, v1, v2, v3}:
	// point = (x + v0 * w + v1 * arcWidth,
	// y + v2 * h + v3 * arcHeight);
	private static double ctrlpts[][] = { { 0.0, 0.0, 0.0, 0.5 },
			{ 0.0, 0.0, 1.0, -0.5 },
			{ 0.0, 0.0, 1.0, -acv, 0.0, acv, 1.0, 0.0, 0.0, 0.5, 1.0, 0.0 },
			{ 1.0, -0.5, 1.0, 0.0 },
			{ 1.0, -acv, 1.0, 0.0, 1.0, 0.0, 1.0, -acv, 1.0, 0.0, 1.0, -0.5 },
			{ 1.0, 0.0, 0.0, 0.5 },
			{ 1.0, 0.0, 0.0, acv, 1.0, -acv, 0.0, 0.0, 1.0, -0.5, 0.0, 0.0 },
			{ 0.0, 0.5, 0.0, 0.0 },
			{ 0.0, acv, 0.0, 0.0, 0.0, 0.0, 0.0, acv, 0.0, 0.0, 0.0, 0.5 }, {}, };
	private static int types[] = { SEG_MOVETO, SEG_LINETO, SEG_CUBICTO,
			SEG_LINETO, SEG_CUBICTO, SEG_LINETO, SEG_CUBICTO, SEG_LINETO,
			SEG_CUBICTO, SEG_CLOSE, };

	/**
	 * Returns the coordinates and type of the current path segment in the
	 * iteration. The return value is the path segment type: SEG_MOVETO,
	 * SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. A float array of
	 * length 6 must be passed in and may be used to store the coordinates of
	 * the point(s). Each point is stored as a pair of float x,y coordinates.
	 * SEG_MOVETO and SEG_LINETO types will return one point, SEG_QUADTO will
	 * return two points, SEG_CUBICTO will return 3 points and SEG_CLOSE will
	 * not return any points.
	 * 
	 * @see #SEG_MOVETO
	 * @see #SEG_LINETO
	 * @see #SEG_QUADTO
	 * @see #SEG_CUBICTO
	 * @see #SEG_CLOSE
	 */
	public int currentSegment(float[] coords) {
		if (isDone()) {
			throw new NoSuchElementException("roundrect iterator out of bounds");
		}
		double ctrls[] = ctrlpts[index];
		int nc = 0;
		for (int i = 0; i < ctrls.length; i += 4) {
			coords[nc++] = (float) (x + ctrls[i + 0] * w + ctrls[i + 1] * aw);
			coords[nc++] = (float) (y + ctrls[i + 2] * h + ctrls[i + 3] * ah);
		}
		if (affine != null) {
			affine.transform(coords, 0, coords, 0, nc / 2);
		}
		return types[index];
	}

	/**
	 * Returns the coordinates and type of the current path segment in the
	 * iteration. The return value is the path segment type: SEG_MOVETO,
	 * SEG_LINETO, SEG_QUADTO, SEG_CUBICTO, or SEG_CLOSE. A double array of
	 * length 6 must be passed in and may be used to store the coordinates of
	 * the point(s). Each point is stored as a pair of double x,y coordinates.
	 * SEG_MOVETO and SEG_LINETO types will return one point, SEG_QUADTO will
	 * return two points, SEG_CUBICTO will return 3 points and SEG_CLOSE will
	 * not return any points.
	 * 
	 * @see #SEG_MOVETO
	 * @see #SEG_LINETO
	 * @see #SEG_QUADTO
	 * @see #SEG_CUBICTO
	 * @see #SEG_CLOSE
	 */
	public int currentSegment(double[] coords) {
		if (isDone()) {
			throw new NoSuchElementException("roundrect iterator out of bounds");
		}
		double ctrls[] = ctrlpts[index];
		int nc = 0;
		for (int i = 0; i < ctrls.length; i += 4) {
			coords[nc++] = (x + ctrls[i + 0] * w + ctrls[i + 1] * aw);
			coords[nc++] = (y + ctrls[i + 2] * h + ctrls[i + 3] * ah);
		}
		if (affine != null) {
			affine.transform(coords, 0, coords, 0, nc / 2);
		}
		return types[index];
	}
}
